Improvement in devices for adjusting piano-forte-action frames



0. P. T. STEINWAY. Device for Adjusting Piano-Forte Aotion Frames.

No. 219,323. Patented Sept. 2,1879.

UNITED STATES PATENT OEEIoE.

CHRISTIAN F. T. STEINWAY, OF NEW YORK, N. Y.

IMPROVEMENT IN DEVICES FOR ADJUSTING PIANO-FORTE-ACTION FRAMES.

Specification forming part of Letters Patent N 0. 219,323, dated.September 2, 1879; application filed July 10,1879.

To all whom it may concern:

Be it known that I, CHRISTIAN FRIEDERICH THEODOR STEINWAY, of the city,county, and State of New York, have invented a new and Improved Devicefor Adjusting the Action- Frames of Piano-Fortes, which invention isfully set forth in the following specification, reference being had tothe accompanying drawings, in which- Figure 1 represents a transversesection in the plane 2 2, Fig. 2. Fig. 2 is a horizontal section in theplane as m, Fig. 1. Fig. 3 is a transverse section in the plane y y,Fig. 2.

Similar letters indicate corresponding parts.

This invention consists in the combination, with the key-block in apiano-forte, of mechanisni adapted to adjust the whole action, with itskey-frame and hammers, forward or back, with relation to the vibratorylengths of the strings, for the purpose of attaining the desiredhammer-line or striking-point for the hammers on the strings.

Herctofore a slot was provided in the keyblock D to receive a pinprojecting from the ends of the key-frame; but by this means only theposition of the key-frame from front to rear in its relation to thestriking-point of the hammers on the strings was unchangeably fixed.

The quality and timbre of the tone, however, depend chiefly upon thehammers striking the strings at certain points in relation to theirlength, which point-s will slightly vary even in instruments of the samekind and construction, and will change by atmospheric i11- fluences, orwhen tuned to a higher or lower pitch, or by other causes.

The object of my invention is to provide means by which the hammerscanat all times be adjusted forward or back, for the purpose ofattaining the proper striking-points on the strings.

In the example shown in the drawings, the letter A designates the bottomof the piano,

' and on this bottom is placed a key-frame, B,

which supports the entire key-board and action. This Whole mechanism, ofwhich B rep resents a part, is fixed in its position on the bottom ofthe piano by a pin, b, (one or more,) which is driven into the ends ofthe key-frame, only one end being shown in the drawings. Said pin 1)engages with a slide, 0, (see Figs. 2 and 3,) which, in the exampleshown, is fitted into a mortise in the key-block D, and it is held inposition by two screws, 0 c, which engage with two slots, (1 d, in theslide, Fig. 3, and screw into the key-block D.

From the back of the slide 0 projects a lug, 0, through which extendsthe plain end of a screw, f, which is tapped into the key-block, asshown in Fig. 2, and is held in the lug e by means of a pin, g, so thatit can be freely turned, and that by its action the slide 0 can be movedbackward or forward, as may be desired.

The head of the screw f is in such a position that it can beconveniently reached with a screw-driver. By turning the screw f theentire key-frame and action is moved backward or forward until thehammers attain the proper striking-point, and then the slide C can befastened in position by the screws 0 c.

What I claim as new, and desire to secure by Letters Patent, is

The combination, with a key block in a piano forte, of a mechanismadapted to adjust the whole action, with its key-frame and hammers,forward or back with relation to the vibratory lengths of the strings,for the purpose of attaining the desired hammer-line or striking-pointsfor the hammers on the strings, substantially as described.

In testimony that I claim the foregoing I have hereunto set my hand andseal this 7th day of July, 1879.

CHRISTIAN FRIEDERICH THEODOR STEINWAY. [L. 3.]

Witnesses:

W. HAUFF, E. F. KASTENHUBER.

